www.pudn.com > 8251-1.rar > 8251-1.ASM
;386以上微机适用
;纯dos下才能使用
;tasm4.1或以上编译
;*********************;
;* 8251 *;
;*********************;
io_plx_device_id equ 05406h ;TPC卡设备ID
io_plx_vendor_id equ 010b5h ;TPC卡厂商ID
IO_PLX_SUB_ID EQU 0905410B5H ;TPC卡子设备及厂商ID
DATA51 EQU 208H-200H ;8251A DATA PORT
CTRL51 EQU 209H-200H ;8251A COMMOND PORT
TIMER2 EQU 202H-200H ;8253 COUNT2
TIMCTL EQU 203H-200H ;8253 CTRL PORT
CLK00 EQU 250 ;8251A CLK 250KHZ
BPS00 EQU 1200 ;BPS=1200
FACTOR EQU 16 ;8251A BPS FACTOR=16
data segment
io_base_address db 4 DUP(0) ;TPC卡I/O基地址暂存空间
pcicardnotfind db 0dh,0ah,'TPC pci card not find or address/interrupt error !!!',0dh,0ah,'$'
iobaseaddress db 0dh,0ah,'TPC pci card I/O Base Address : ','$'
enter_return db 0dh,0ah,'$'
MES DB 'NOW YOU CAN PLAY A KEY ON THE CPU_KEYBORD',0AH,0DH
DB 'IT WILL DISPLAY ON THE TERMINAL_SCREEN' ,0AH,0DH
DB 'OR YOU CAN PRESS A KEY ON THE TERMINAL KEYBOARD',0AH,0DH
DB 'IT WILL DISPLAY ON THE CPU_SCREEN ',0AH,0DH
DB 'PRESS ESC_KEY CAN FINISH COMMUNICATION',0AH,0DH,'$'
data ends
stacks segment
db 100 dup (?)
stacks ends
code segment
assume cs:code,ds:data,ss:stacks,es:data
start:
.386
cli
mov ax,data
mov ds,ax
mov es,ax
mov ax,stacks
mov ss,ax
call findtpc ;查找TPC卡资源并显示
CALL SET_BPS ;初始化8253
CALL INIT51
MOV AX,DATA ;DISPLAY MES
MOV DS,AX
LEA DX,MES
MOV AH,09
INT 21H
FOREVER:
MOV DX,word ptr io_base_address
add dx,CTRL51
IN AL,DX
TEST AL,02
JNZ RECEIVE
MOV AH,01 ;INPUT A CHAR FROM CPU_KEYBORD
INT 16H
JZ FOREVER
MOV AH,0
INT 16H
CMP AL,1BH
JZ EXIT
MOV DX,word ptr io_base_address
add dx,DATA51
OUT DX,AL ;CPU OUTPUT THE CHAR TO 8251A
mov dl,al
mov ah,02
int 21h
JMP FOREVER
RECEIVE:
MOV DX,word ptr io_base_address
add dx,DATA51
IN AL ,DX
CMP AL,1BH
JZ EXIT
MOV DL,AL
inc dl
MOV AH,02
INT 21h
JMP FOREVER
EXIT: MOV AX,4C00H
INT 21H ;退出
INIT51 PROC NEAR ;INIT 8251A
MOV DX,word ptr io_base_address
add dx,CTRL51
XOR AX,AX
MOV CX,03
LL: CALL CHAROUT
LOOP LL
MOV AL,40H ;RESET 8251A
CALL CHAROUT
mov al,4eh ;DATA 8 BIT,STOP 1 BIT,FACTOR=16
call charout
MOV AL,27H ;ENABLE INPUT AND OUTPUT
CALL CHAROUT
RET
INIT51 ENDP
CHAROUT PROC NEAR ;OUTPUT A BYTE
OUT DX,AL
PUSH CX
MOV CX,20h
GG: LOOP GG
POP CX
RET
CHAROUT ENDP
SET_BPS PROC NEAR ;T/R CLOCK FROM TIMER2
MOV DX,0
MOV AX,CLK00
MOV BX,1000 ;COUNT2=CLK00*1000/FACTOR/BPS00
MUL BX
MOV BX,BPS00
DIV BX
MOV DX,00
MOV BX,FACTOR
DIV BX
MOV BX,AX
MOV DX,word ptr io_base_address
add dx,TIMCTL ;TIMER2 IN MODE3
MOV AL,0B6H
OUT DX,AL
MOV DX,word ptr io_base_address
add dx,TIMER2
MOV AX,BX
OUT DX,AL
MOV AL,AH
OUT DX,AL
RET
SET_BPS ENDP
findtpc proc near ;查找TPC卡资源并显示
pushad
pushfd
MOV AX,0B101H
INT 1AH
JC findtpc_notfind ;检查PCI BIOS是否存在
MOV AX,0B102H
MOV CX,io_plx_device_id
MOV DX,io_plx_vendor_id
MOV SI,0
INT 1AH
JC findtpc_notfind ;检查TPC卡是否安装,设备号、厂商号
MOV AX,0B10AH
MOV DI,02CH
INT 1AH
JC findtpc_notfind
CMP ECX,IO_PLX_SUB_ID
JNZ findtpc_notfind ;检查TPC卡是否安装,子设备号、厂商号
MOV AX,0B10AH
MOV DI,18H
INT 1AH
JC findtpc_notfind ;读TPC卡I/O基址信息
mov dword ptr io_base_address,ecx
and ecx,1
jz findtpc_notfind ;检查是否为i/o基址信息
mov ecx,dword ptr io_base_address
and ecx,0fffffffeh
mov dword ptr io_base_address,ecx ;去除i/o指示位并保存
mov dx,offset iobaseaddress ;显示i/o提示信息
mov ah,09h
int 21h
mov ax,word ptr io_base_address
call dispword ;显示i/o基地址
mov dx,offset enter_return ;加回车符,换行符
mov ah,09h
int 21h
popfd
popad
ret
findtpc_notfind:
mov dx,offset pcicardnotfind ;显示未找到tpc卡提示信息
mov ah,09h
int 21h
mov ax,4c00h
int 21h ;退出
findtpc endp
dispword proc near ;显示子程序
push dx
push cx
push bx
mov cx,4
mov bx,16
dispword_loop1:
push ax
push cx
sub bx,4
mov cx,bx
shr ax,cl
and al,0fh ;首先取低四位
mov dl,al
cmp dl,9 ;判断是否<=9
jle dispword_num ;若是则为'0'-'9',ASCII码加30H
add dl,7 ;否则为'A'-'F',ASCII码加37H
dispword_num:
add dl,30h
mov ah,02h ;显示
int 21h
pop cx
pop ax
loop dispword_loop1
pop bx
pop cx
pop dx
ret ;子程序返回
dispword endp
code ends
end start